The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 16, 1999
Filed:
Jun. 13, 1996
Tadashi Adachi, Tokyo, JP;
NEC Corporation, , JP;
Abstract
An apparatus for exposing an optical master disk includes an exposure section, an exposure control section, a guide groove exposure voltage supplier and a modulator. The exposure section is for exposing a guide groove and pre-pits by different laser beams, and the exposure control section is for controlling an exposure voltage of the laser beams in the exposure section and an exposure timing. The guide groove exposure voltage supplier is for supplying, in accordance with the pre-pit designation signal, to the exposure section a guide groove exposure voltage of a first power level when an inside or an outside guide groove adjacent to the pre-pits is exposed and a guide groove exposure voltage of a second power level when a guide groove not adjacent to the pre-pits is exposed. The modulator modulates a laser beam for exposing the guide groove in accordance with the guide groove exposure voltage. In this way, the groove shape of the guide groove adjacent to the pre-pits and that of the guide groove not adjacent to the pre-pits are made uniform.